With emergence of various information services, storage of data has been developed. Today, data to be downloaded by end users are typically stored at cache servers, from which the end users obtains data. WEB-servers are also referred to as caches and the term caches will be used in this description.
Each cache has a unique IP (Internet Protocol)-address, which is used to identify the cache when requesting data to be downloaded. Which cache to select for a specific service request, is based on the URL information that is translated into IP address by DNS lookup procedure. Typical information services where end users download data are web-page browsing, streamed music listening, streamed video watching, IPTV, streamed text reading, etc.
The term “object data” will be used throughout this description to denote data of object. Examples of objects may be elements or parts of any of: a web-page, a streamed session of music, video or text, a media file, an executable SW code, etc. An object is a specific information element of a Web page, etc., packetized as an object with its own unique DNS (Domain Name System) name pointing to a specific place where the object is stored. An object may be a static set of data, but may also vary dynamically with time. The content can also be created at the request of the content.
By distributing object data on a plurality of caches and arrange the caches at suitable locations, data traffic capacity may be optimised to meet the end user's needs. The same object may for instance be stored at a plurality of locations.
Thereby, the end user may select to download objects from domestic caches or will be redirected to domestic caches instead of downloading from caches abroad. Thereby load on bottlenecks, as intercontinental communication links, may be decreased and the end users may download the objects faster.
With reference to FIG. 1, which is a schematic overview, a scenario of retrieving object data will now be described.
In a caching system 100 objects of a web-page are distributed over a plurality of caches 102a, 102b, 102c. When an end user retrieves an object, his/her UE (User Equipment) 104 sends an http request, where the location of the object and the name of the object are included. For instance, the http request may be http-get://Cache_1/object_1, where Cache_1 is the domain name which is translated to an IP-address to the first cache 102a. In response to the http request, the first cache 102a returns the first object. The first cache 102a has information regarding that a second object, i.e. the subsequent object, is stored at a second cache 102b. The first cache 102a redirects the UE 104 to the second cache 102b, by sending the a new URL (which is translated to another IP-address to the second cache) of the second cache 102b to the UE 104, e.g. implemented as http-response Cache_2, where Cache_2 is the domain name of the second cache IP address of the second cache 102b. Each of the caches has knowledge of where subsequent objects to be retrieved are stored, e.g. the second cache 102b has information regarding a third object and will redirect to the third cache 102c. 
In order to balance the load further in distributed caching systems there is a trend to increase the number of objects to be distributed and to distribute individual objects more widely. However, division of data into smaller objects is counteracted, e.g. due to the fact that the client has to respond to each redirecting between the caches, and that http redirecting is slow.
Thus there is a need to devise a faster retrieval of object data in distributed caching systems.